"The
effect of state duty to warn laws inspired by Tarasoff v. Regents has
been debated for decades. Required reporting of patient threats to the
authorities and potential victims gives incentive to the mental health
professional to not meet with the most at risk patients, or at very
least make the current state of the law abundantly clear to the patient
as to suggest suppression of the most at risk statements leaving the
psychologist in liability-free ignorance to the true mental state of
the patient. As a result, the mental help needed to treat the patient
may be foregone and violence may ensue. Exploiting the variation in the
timing and style of duty to warn laws across states, I use a fixed
effects model to find that, all else equal and controlling for the
prevalence of crack, mandatory duty to warn laws cause an increase in
homicides of 9.5% or 0.83 people per 100,000. These results are robust
to model specifications, falsification tests, and help to clarify the
true, albeit unintended, affect of state duty to warn laws."